_____ is a good form of exercise for both young and old.
| A．Walk | B．Walking |
| C．The walk | D．To walk |
This morning, I rushed to the library, only ________ that its door was still locked.
| A．to be found | B．to find |
| C．finding | D．found |
_______ with so much trouble, we failed to complete task on time.
| A．Faced | B．Face |
| C．Facing | D．To face |
What we should be thinking about now is how to make up for the lost time, not who is _______.
| A．blaming | B．blamed |
| C．to be blamed | D．to blame |
It is your attitude, rather than your aptitude(天资), ________ determines your altitude.
| A．which | B．that | C．what | D．who |
The birds that will spend the whole winter here have been digging holes in the snow _______ from the cold weather.
| A．to shelter | B．sheltered |
| C．having sheltered | D．sheltering |